v 
96 FISHES AND FISH DEVELOPMENT—PIERS. 
This fish first appears with the mackerel. It associates with 
the jelly fish, which are sometimes observed “accompanied by 
ten or twelve, or more, young Butter-fishes, which seem to seek 
shelter under their disks, and which, perhaps, may obtain a 
supply of food from among the numerous soft-bodied inverte- 
brates which are constantly becoming attached to the floating 
streamers of their protectors.” Fifteen have thus been seen 
under a Cyanea arctica only three inches in diameter. Their 
entertainer, however, does not always prove a good host, “for 
they sometimes are destroyed by the tentacles of their protector, 
which are provided, as every one knows, with powerful lasso 
cells.” Their flesh is excellent as an article of food, and 
resembles in flavor that of the mackerel. It is remarkable for 
its “brilliant, iridescent colors, which, in freshly caught in- 
dividuals, are as beautiful as those of a dolphin.” The fact of 
_its appearing during harvest time gave it its common name. 
Our fishermen call it the Dollar-fish. 
AMERICAN ASPIDOPHORE — Aspidophoroides monopterygius, 
STORER. 
This rare and curious fish was collected on the shore of Cape 
Breton. It is more frequently observed on the coast of Green- 
land, and, although “not much thinner or softer than an iron 
spike,’ it is sometimes taken, by our fishermen, from the 
stomachs of codfish and halibut eanght on the Banks. 
DeKay gives but an imperfect figure of this species, and our 
specimen, now before me, appears to differ in the following par- 
ticulars. The anal fin has six rays instead of five, and it com- 
mences slightly anterior to a point beneath the beginning of the 
dorsal and ends the same distance in front of the termination of 
the latter. The pectoral is nearly three times as long as that 
in the figure, the fourth ray being the longest. Our fish is also 
of much greater height just in advance of the pectorals and the 
breadth here is 1lmm. But the chief difference appears to lie 
in the absence of the third spine on the snout, which latter is 
also more acute. The total length is a little over 16mm, 
